The activation of GPER can stimulate its downstream signals including mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), and epidermal growth factor receptors (EGFRs) [14], then modulate growth of hormonally responsive cancers such as endometrial [15], ovarian [16], and breast cancer [17]. This evidence concerns the gene GPER1 and cancer.